Sexism is certainly evident in Harper Lee's novel To Kill a Mockingbird. Examples of quotes which depict sexism in the novel are as follows:

Mr. Conner said he knew who each and every one of them was, and he was bound and determined they wouldn’t get away with it, so the boys came before the probate judge on charges of disorderly conduct, disturbing the peace, assault and battery, and using abusive and profane language in the presence and hearing of a female.

In chapter one, this passage depicts the fact that certain language is expected in front of a woman. While some may look at this as respectful, others may find this a sexist idea.

Aunt Alexandra was fanatical on the subject of my attire. I could not possibly hope to be a lady if I wore breeches; when I said I could do nothing in a dress, she said I wasn’t supposed to be doing things that required pants.

Here, (from chapter nine) Aunt Alexandra expects Scout to act as a proper lady. Scout is not able to simply be a child. Instead, Scout was only expected (by Aunt Alexandra) to dress and act like a lady. This can be perceived as a sexist idea given that her behavior is simply based upon her gender.

In chapter twenty, Dill is depicted as being truly male. According to Dill, men (or boys) are not supposed to cry. Crying, according to sexist thought, is only something a girl, or woman, does.

“Gentlemen,” he said. Jem and I again looked at each other: Atticus might have said, “Scout.” His voice had lost its aridity, its detachment, and he was talking to the jury as if they were folks on the post office corner.

Also found in chapter twenty is the fact that the entire jury is male. No women were allowed to set on the jury and decide upon cases.